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Hope this help the students who study sound and vibration but don't have Chegg ID. Questions Answers

Hope this help the students who study sound and vibration but don't have Chegg ID. Questions :Duct Noise 1. For the duct with infinity long, when the particle velocity in root mean square value is 0.002m/s, calculate the sound pressure level. 2. For the duct with cross-sectional area of 150mm times 150mm, if the speaker generate sound at 300Hz,    1)Write down the general formula to describe the waveform.   2) If the amplitude of incident pressure is 5 Pa, what is the sound pressure level at a distance of 1m from the loudspeaker with the assumption of anechoic termination?    3) If the amplitude of reflection wave is 2 Pa when the anechoic termination is replaced by other absorption material, what is the sound pressure level at a distance of 1m from the speaker by keeping amplitude of incident wave 5 Pa.   3.  As shown in Fig, the amplitude of incident wave is 3 Pa, the reflection coefficient is 0.6, calculate the sound pressure level and sound intensity level

Hope this help the students who study sound and vibration but don't have Chegg ID. Questions 1.  What is the change in sound pressure level from a uniform radiating source, if (a) the intensity is doubled? (b) the pressure is doubled? (c) two more identical sources are added in locations equivalent to the first 2. Calculate the % of acoustical energy that must be removed to reduce a given SPL by 1dB; by 5dB; by 10dB 3.  80dB + 76dB = ? 4. You have available to you two pump styles : pump A at 80 l/s produces a 100 dBA SPL at a given point, and pump B at 40 l/s produces 90dBA under the same condition. From a noise control standpoint, what combination of pumps would be the most acceptable for developing a flow rate of 160 l/s? 5. The noise level from a power station with 10 identical transformers measured near some residential property line was found to be 54dB. The maximum permitted in this area is 51d